Tag Archives: arsenic

Books can be toxic (literally)

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I do love word play although I am pushing it a bit with ‘book’, ‘literature’, and ‘literal’.

These poison books each contain heavy metals used to create striking colours [in] the 1800s. Source: Museums Victoria Photo: Rob French [downloaded from https://museumsvictoria.com.au/article/if-books-could-kill-poison-heavy-metal-and-literature/]

Mark Lorch’s, Professor of Science Communication and Chemistry at the University of Hull (UK), April 29, 2024 essay on The Conversation (h/t April 30, 2024 news item on phys.org) provides an interesting account of the dangers associated with literature, Note: Links have been removed,

In our modern society, we rarely consider books to be dangerous items. However, certain books contain elements so hazardous that they require scrutiny before being placed on the shelves of public libraries, bookstores or even private homes.

The Poisonous Book Project [also known as, Poison Book Project], a collaborative research project between Winterthur Museum, Garden & Library and the University of Delaware, is dedicated to cataloguing such books. Their concern is not with the content written on the pages, but with the physical components of the books themselves — specifically, the colours of the covers.

The project recently influenced the decision to remove two books from the French national library. The reason? Their vibrant green cloth covers raised suspicions of containing arsenic.

This concern is rooted in historical practices in bookbinding. During the 19th century, as books began to be mass produced, bookbinders transitioned from using expensive leather covers to more affordable cloth items. To attract readers, these cloth covers were often dyed in bright, eye-catching colours.

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One popular pigment was Scheele’s green, named after Carl Wilhelm Scheele, a German-Swedish chemist who in 1775 discovered that a vivid green pigment could be produced from copper and arsenic. This dye was not only cheap to make, it was also more vibrant than the copper carbonate greens that had been used for over a century.

Scheele green eventually fell out of favour because it had a tendency to fade to black when it reacted with sulphur-based pollutants released from coal. But new dyes based on Scheele’s discovery, such as emerald and Paris green, proved to be much more durable. …

These pigments, however, had a significant drawback: they degraded easily, releasing poisonous and carcinogenic arsenic. The frequent reports of green candles poisoning children at Christmas parties, factory workers tasked with applying paint to ornaments convulsing and vomiting green water and warnings of poisonous ball dresses raised serious concerns about the safety of these green dyes.

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Green isn’t the only colour to worry about, however. Red is also of concern. The brilliant red pigment vermilion was formed from the mineral cinnabar, also known as mercury sulfide. This was a popular source of red paint dating back thousands of years. There is even evidence that neolithic artists suffered from mercury poisoning. Vermilion red sometimes appears on the marbled patterns on the inside of book covers.

Yellow has also caught the eye of the poisonous book project. In this case, the culprit is lead chromate. The bright yellow of lead chromate was a favourite with painters, not least Vincent van Gogh, who used it extensively in his most famous series of paintings: Sunflowers. For the Victorian-era bookbinders, lead chromate allowed them to create a range of colours from greens (achieved by mixing chrome yellow with Prussian blue) to yellows, oranges and browns.

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So what should you do if you come across a green cloth book from the 19th century? First, don’t be overly concerned. You would probably have to eat the entire book before you’d suffer from severe arsenic poisoning. However, casual exposure to copper acetoarsenite, the compound in the green pigment, can irritate the eyes, nose and throat.

It is more of a concern for folks who may regularly handle these books where frequent contact could result in more serious symptoms. Therefore, anyone who suspects they might be handling a Victorian-era book with an emerald green binding is advised to wear gloves and avoid touching their face. Then clean all surfaces afterwards.

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If you have a bit of time, Lorch’s April 29, 2024 essay is fascinating. If you have more time, there’s the undated “If books could kill: poison, heavy metal and literature” article on the Museums Victoria (Australia) website,

Books are not usually thought of as hazardous objects, but you will want to be careful with these ones from the Melbourne Museum’s Rare Book Collection.

Poisonous heavy metals permeate their very fabric, and the last 150-odd years has done nothing to lessen their toxicity.

How did it happen though?

This is not some dastardly Name of the Rose-esque plot [a reference to Umberto Eco and his 1986 novel, The Name of the Rose] but rather a combination of fashion, vanity, and workers’ rights (or lack thereof) in the years following the Industrial Revolution.

And it has left a dangerous legacy for modern-day museums.

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Lastly, you can find the Poison Book Project here.

Phytoremediation with lupin and arsenic

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Is anyone else reminded of Arsène Lupin? (More about Lupin later in this posing)

An August 24, 2021 news item on ScienceDaily describes research on soils and phytoremediation (decontamination by plants),

Pollution of soils with highly toxic arsenic is a worldwide problem generating substantial risks to human health and the environment.

In Canada, over 7000 sites contaminated with metals such as arsenic are considered ‘highly concerning’ by the government, with some past and recent mining operations and wood preservative facilities having left their mark on the environment by increasing soil arsenic levels by up to 1000 times the maximum regulatory health limits.

One way in which arsenic contaminated soils could be rejuvenated is to exploit natural mechanisms which have evolved in certain plants for contamination tolerance.

“The legume crop white lupin (L. albus) is one such arsenic tolerant plant species being studied as for sustainable remediation,” explains Adrien Frémont, lead author of the study and a doctoral student in biological sciences at the Université de Montréal. “The mechanism behind arsenic tolerance in white lupin is thought to be the release of plant chemicals directly into soil by roots, but the nature of these compounds is unknown and hard to study due to the complexity of these belowground interactions.”

Caption: The legume crop white lupin (L. albus) is one such arsenic tolerant plant species being studied as for sustainable remediation. Credit: UMONTREAL

An August 24, 2021 University of Montreal (Université de Montréal) news release (also on EurekAlert), which originated the news item, describes the work in more detail,

Root chemicals an undiscovered country

To study this, the team developed nylon pouches which could be placed close to roots in soil to capture exuded molecules without damaging the root system. The complex mix of molecules collected from these pouches were analysed using advanced (metabolomic) chemical profiling to identify the compounds capable of binding metals produced by the Lupin plants in response to high concentrations of arsenic. Some of these metal-binding molecules, phytochelatins, are known to be used internally by plants to deal with metal stress but have never before been captured as exuded into polluted soils.

“We’re really excited to see how matching new root-soil sampling approaches with advanced metabolomic profiling can yield such unexpected discoveries”, notes Frémont. “We know that plants can drastically change soil properties and can transform or immobilise soil pollution, but the chemistry underlying how they achieve this, and in particular the makeup and function of root-exuded compounds, is still very much an undiscovered country.”
 

Plant roots directly altering polluted soils

The next steps of the research are to branch out into more detailed analysis of the precise chemical reactions taking place at the root-soil interface, including exploration of different plant species, interactions with microorganisms and the challenge of diverse soil pollution.

As Dr. Nicholas Brereton, University of Montreal and the study’s senior author, mentions: “It can be a real challenge to research the complex interactions going on belowground between plants and soil, but these findings are rewarding in telling us that natural mechanisms have evolved in plants to deal with this type of pollution. Although we’re still only just beginning to scratch below the surface of how these plant root strategies work, as we learn more, we can potentially utilise these natural processes to improve soil health and help to alleviate some of the most persistent anthropogenic damage to our environment.”

Here’s a link to and a citation for the paper,

Phytochelatin and coumarin enrichment in root exudates of arsenic-treated white lupin by Adrien Frémont, Eszter Sas, Mathieu Sarrazin, Emmanuel Gonzalez, Jacques Brisson, Frédéric Emmanuel Pitre, Nicholas James Beresford Brereton. Plant Cell & Environment DOI: https://doi.org/10.1111/pce.14163 First published: 15 August 2021

This paper is behind a paywall.

For anyone interested in phytoremediation, I have a March 30, 2012 posting about it and there’s this Wikipedia entry. Depending on the circumstances, you might also consider phytoremediation as a form of phyto-mining, i.e., using plants to recover metals from mine tailings (see my March 5, 2013 posting).

Arsène Lupin

There are two of them (the first and the latest ones) being mentioned here; but there are many versions of Arsène Lupin in manga, anime, movies, etc.

The first fictional Arsène Lupin was created in 1905 by Maurice Leblanc. Here’s a description (on the Normandie tourisme website) of the first Lupin in an article about the latest Lupin, a series streamed on Netflix.

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Maurice Leblanc was born in Rouen in 1864. Fascinated by legends of witches, Celts, Romans and the Vikings growing up, Leblanc would go on to develop a deep knowledge of and love for the region around Rouen, known as the Pays de Caux. After working in a factory in Rouen by day, writing only in his spare time, Leblanc eventually left his home town to study in Paris, where he then started working as a journalist for several publications including Le Figaro. Fate then struck, as publisher Pierre Lafitte launched the magazine Je sais tout and commissioned Leblanc to write a series of new crime stories where the hero would be a sort of French anti-Sherlock Holmes.

Who was the original Lupin? Not unlike Lupin in the TV series, the Arsène Lupin of the books was a thief, a master of disguise, a rascal but never a killer, a hit with the ladies and a righter of wrongs who takes from the rich, a French Robin Hood if you like. He takes on a multitude of personas in the books, constantly changing his looks and his name – examples include Prince Paul Sernine, Raoul d’Andrésy, Horace Velmont and Don Luis Perenna. In the [Lupin] series [2021], this is echoed by Assane’s alter-egos Paul Sernine, Luis Perenna and Salvatore813, as well as his choice of name for his son, Raoul. Yet superman Lupin, both in the books and on screen, always manages to triumph somehow over his enemies, even when all seems lost, through bending the rules, outsmarting the police and sheer self-belief.

You can find out more about the latest Lupin in its IMDb entry,

Inspired by the adventures of Arsène Lupin, gentleman thief Assane Diop sets out to avenge his father for an injustice inflicted by a wealthy family.

The television series starring Omar Sy was a huge hit in France and has been seen worldwide.

Canadian and Guadeloupean oysters: exposure to nanoplastics and arsenic

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A May 27, 2021 news item on phys.org describes research into oysters and nanoplastics,

Oysters’ exposure to plastics is concerning, particularly because these materials can accumulate and release metals which are then absorbed by the mollusks. According to a recent study published in the journal Chemosphere, the combined presence of nanoplastics and arsenic affects the biological functions of oysters. This study was conducted by the Institut national de la recherche scientifique (INRS) in Québec City and the French National Centre for Scientific Research (CNRS) at the University of Bordeaux in France

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A May 27, 2021 INRS news release (French language version here and an English language version on EurekAlert), which originated the news item, provides fascinating details,

The international research team chose to study arsenic, since it is one of the most common metals absorbed by the plastic debris collected from the beaches of Guadeloupe. “Oysters easily accumulate metals from the environment into their tissues. We therefore wanted to test whether the combined exposure to nanoplastics and arsenic would increase the bioaccumulation of this contaminant,” reported Marc Lebordais, the Master’s student in charge of the research.

The scientists proved that the bioaccumulation of arsenic does not increase when nanoplastics are also present. However, it remained higher in the gills of the Canadian Crassostrea virginica oyster [emphasis mine] than in the Isognomon alatus oyster, found in Guadeloupe. These results are the first to highlight the diverging sensitivity of different species. [emphasis mine]

Gene deregulation

In addition to bioaccumulation, the team also observed an overexpression of genes responsible for cell death and the number of mitochondria–a cell’s energy centres–in C. virginica. In I. alatus, the expression of these same genes was less significant.

“Evaluating the expression of genes involved in important functions, such as cell death and detoxification, gives us information on the toxicity of nanoplastics and arsenic on a cellular level,” explained the young researcher, who is co-directed by Professors Valérie Langlois of INRS and Magalie Baudrimont of the University of Bordeaux.

The food chain

The next step, after characterizing the presence of nanoplastics and arsenic in oysters, would be to study how these contaminants are transferred through the food chain.

“Analytical tools are currently being developed to quantify the presence of nanoplastics in biological tissues,” said Marc Lebordais. “Understanding the amount of nanoplastics in farmed oysters currently boils down to a technical issue.” ?

Here’s a link to and a citation for the paper,

Molecular impacts of dietary exposure to nanoplastics combined with arsenic in Canadian oysters (Crassostrea virginica) and bioaccumulation comparison with Caribbean oysters (Isognomon alatus) by Marc Lebordais, Juan Manuel Gutierrez-Villagomez, Julien Gigault, Magalie Baudrimont, and Valérie Langlois. Chemosphere Volume 277, August 2021, 130331 DOI: https://doi.org/10.1016/j.chemosphere.2021.130331 First published online 19 March 2021.

This paper is open access.

Living plants detect arsenic by way of embedded nanosensors

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There’s a lot of arsenic in the world and it’s often a factor in making water undrinkable. When that water is used in farming It also pollutes soil and enters food-producing plants. A December 11, 2020 news item on Nanowerk announces research into arsenic detectors in plants,

Researchers have developed a living plant-based sensor that can in real-time detect and monitor levels of arsenic, a highly toxic heavy metal, in the soil. Arsenic pollution is a major threat to humans and ecosystems in many Asia Pacific countries.

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Caption: Non-destructive plant nanobionic sensor embedded within leaves to report arsenic levels within plants to portable electronics, enabling real-time monitoring of arsenic uptake in living plants. Credit: Dr. Tedrick Thomas Salim Lew

I was not able to find the source for the news item but I did locate something close. From a December 13, 2020 Singapore-Massachusetts Institute of Technology (MIT) Alliance for Research and Technology (SMART), also on EurekAlert,

Scientists from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) research group at the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, have engineered a novel type of plant nanobionic optical sensor that can detect and monitor, in real time, levels of the highly toxic heavy metal arsenic in the underground environment. This development provides significant advantages over conventional methods used to measure arsenic in the environment and will be important for both environmental monitoring and agricultural applications to safeguard food safety, as arsenic is a contaminant in many common agricultural products such as rice, vegetables, and tea leaves.

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Arsenic and its compounds are a serious threat to humans and ecosystems. Long-term exposure to arsenic in humans can cause a wide range of detrimental health effects, including cardiovascular disease such as heart attack, diabetes, birth defects, severe skin lesions, and numerous cancers including those of the skin, bladder, and lung. Elevated levels of soil arsenic as a result of anthropogenic activities such as mining and smelting are also harmful to plants, inhibiting growth and resulting in substantial crop losses.

Food crops can absorb arsenic from the soil, leading to contamination of food and produce consumed by humans. Arsenic in underground environments can also contaminate groundwater and other underground water sources, the long-term consumption of which can cause severe health issues. As such, developing accurate, effective, and easy-to-deploy arsenic sensors is important to protect both the agriculture industry and wider environmental safety.

The novel optical nanosensors exhibit changes in their fluorescence intensity upon detecting arsenic. Embedded in plant tissues, with no detrimental effects on the plant, these sensors provide a nondestructive way to monitor the internal dynamics of arsenic taken up by plants from the soil. This integration of optical nanosensors within living plants enables the conversion of plants into self-powered detectors of arsenic from their natural environment, marking a significant upgrade from the time- and equipment-intensive arsenic sampling methods of current conventional methods.

“Our plant-based nanosensor is notable not only for being the first of its kind, but also for the significant advantages it confers over conventional methods of measuring arsenic levels in the below-ground environment, requiring less time, equipment, and manpower,” says Lew. “We envision that this innovation will eventually see wide use in the agriculture industry and beyond. I am grateful to SMART DiSTAP and the Temasek Life Sciences Laboratory (TLL), both of which were instrumental in idea generation and scientific discussion as well as research funding for this work.”

Besides detecting arsenic in rice and spinach, the team also used a species of fern, Pteris cretica, which can hyperaccumulate arsenic. This fern species can absorb and tolerate high levels of arsenic with no detrimental effect — engineering an ultrasensitive plant-based arsenic detector, capable of detecting very low concentrations of arsenic, as low as 0.2 parts per billion. In contrast, the regulatory limit for arsenic detectors is 10 parts per billion. Notably, the novel nanosensors can also be integrated into other species of plants. The researchers say this is the first successful demonstration of living plant-based sensors for arsenic and represents a groundbreaking advancement that could prove highly useful in both agricultural research (e.g., to monitor arsenic taken up by edible crops for food safety) and general environmental monitoring.

Previously, conventional methods of measuring arsenic levels included regular field sampling, plant tissue digestion, extraction, and analysis using mass spectrometry. These methods are time-consuming, require extensive sample treatment, and often involve the use of bulky and expensive instrumentation. The new approach couples nanoparticle sensors with plants’ natural ability to efficiently extract analytes via the roots and transport them. This allows for the detection of arsenic uptake in living plants in real time, with portable, inexpensive electronics such as a portable Raspberry Pi platform equipped with a charge-coupled device camera akin to a smartphone camera.

Co-author, DiSTAP co-lead principal investigator, and MIT Professor Michael Strano adds, “This is a hugely exciting development, as, for the first time, we have developed a nanobionic sensor that can detect arsenic — a serious environmental contaminant and potential public health threat. With its myriad advantages over older methods of arsenic detection, this novel sensor could be a game-changer, as it is not only more time-efficient, but also more accurate and easier to deploy than older methods. It will also help plant scientists in organizations such as TLL to further produce crops that resist uptake of toxic elements. Inspired by TLL’s recent efforts to create rice crops which take up less arsenic, this work is a parallel effort to further support SMART DiSTAP’s efforts in food security research, constantly innovating and developing new technological capabilities to improve Singapore’s food quality and safety.”

The research is carried out by SMART and supported by the National Research Foundation (NRF) Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) program.

Led by MIT’s Strano and Singapore co-lead principal investigator Professor Chua Nam Hai, DiSTAP is one of the five Interdisciplinary Research Groups (IRGs) in SMART. The DiSTAP program addresses deep problems in food production in Singapore and the world by developing a suite of impactful and novel analytical genetic and biosynthetic technologies. The goal is to fundamentally change how plant biosynthetic pathways are discovered, monitored, engineered, and ultimately translated to meet the global demand for food and nutrients. Scientists from MIT, TTL, Nanyang Technological University, and National University of Singapore are collaboratively developing new tools for the continuous measurement of important plant metabolites and hormones for novel discovery, deeper understanding and control of plant biosynthetic pathways in ways not yet possible, especially in the context of green leafy vegetables; leveraging these new techniques to engineer plants with highly desirable properties for global food security, including high yield density production, drought and pathogen resistance and biosynthesis of high-value commercial products; developing tools for producing hydrophobic food components in industry-relevant microbes; developing novel microbial and enzymatic technologies to produce volatile organic compounds that can protect and/or promote growth of leafy vegetables; and applying these technologies to improve urban farming.

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Here’s a link to and a citation for the paper,

Plant Nanobionic Sensors for Arsenic Detection by Tedrick Thomas Salim Lew, Minkyung Park, Jianqiao Cui, Michael S. Strano. Advanced Materials DOI: https://doi.org/10.1002/adma.202005683 First published: 26 November 2020

This paper is behind a paywall.

Two-dimensional arsenic (arsenene) for electronics

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Another day, another ‘ene’ (e.g., graphene, borene, germanene, etc.). This ‘ene’ is arsenene, from an October 15, 2018 Wiley (Publications) news release (also on EurekAlert),

The discovery of graphene, a material made of one or very few atomic layers of carbon, started a boom. Today, such two-dimensional materials are no longer limited to carbon and are hot prospects for many applications, especially in microelectronics. In the journal Angewandte Chemie, scientists have now introduced a new 2D material: they successfully modified arsenene (arsenic in a graphene-like structure) with chloromethylene groups.

Two-dimensional materials are crystalline materials made of just a single or very few layers of atoms that often display unusual properties. However, the use of graphene for applications such as transistors is limited because it behaves more like a conductor than a semiconductor. Modified graphene and 2D materials based on other chemical elements with semiconducting properties have now been developed. One such material is β-arsenene, a two-dimensional arsenic in a buckled honeycomb structure derived from gray arsenic. Researchers hope that modification of this previously seldom-studied material could improve its semiconducting properties and lead the way to new applications in fields such as sensing, catalysis, optoelectronics, and other semiconductor technologies.

A team at the University of Chemistry and Technology Prague (Czech Republic) and Nanyang Technical University (Singapore), led by Zdenek Sofer and Martin Pumera has now successfully produced a highly promising covalent modification of β-arsenene.

The arsenene was produced by milling gray arsenic in tetrahydrofuran. The shear forces cause two-dimensional layers to split off and disperse into the solvent. The researchers then introduce dichloromethane and add an organic lithium compound (butyllithium). These two reagents form an intermediate called chlorocarbene, a molecule made of one carbon atom, one hydrogen atom, and one chlorine atom. The carbon atom is short two bonding partners, a state that makes the whole class of carbene molecules highly reactive. Arsenene contains free electron pairs that “stick out” from the surface and can easily enter into bonds to chlorocarbene.

This approach leads to high coverage of the arsenene surface with chloromethylene groups, as confirmed by a variety of analysis methods (X-ray photoelectron spectroscopy, FT-IR spectroscopy, elemental analysis by transmission electron microscopy). The modified arsenene is more stable than pure arsenene and exhibits strong luminescence and electronic properties that make it attractive for optoelectronic applications. In addition, the chloromethylene units could serve as a starting point for further interesting modifications.

As always with an ‘ene’, the major focus is on electronics. Here’s a link to and a citation for the paper,

Covalent Functionalization of Exfoliated Arsenic with Chlorocarbene by Jiri Sturala, Adriano Ambrosi, Zdeněk Sofer, Martin Pumera. Angewandte Chimie International Edition Volume 57, Issue 45 November 5, 2018 Pages 14837-14840 DOI: https://doi.org/10.1002/anie.201809341 First published: 31 August 2018

This paper is behind a paywall.

‘Hunting’ pharmaceuticals and removing them from water

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Pharmaceuticals are not the first pollutants people think of when discussing water pollution but, for those who don’t know, it’s a big issue and scientists at the University of Surrey (UK) have developed a technology they believe will help to relieve the contamination. From an April 10, 2017 University of Surrey press release (also on EurekAlert),

The research involves the detection and removal of pharmaceuticals in or from water, as contamination from pharmaceuticals can enter the aquatic environment as a result of their use for the treatment of humans and animals. This contamination can be excreted unchanged, as metabolites, as unused discharge or by drug manufacturers.

The research has found that a new type of ‘supermolecule’, calix[4], actively seeks certain pharmaceuticals and removes them from water.

Contamination of water is a serious concern for environmental scientists around the world, as substances include hormones from the contraceptive pill, and pesticides and herbicides from allotments. Contamination can also include toxic metals such as mercury, arsenic, or cadmium, which was previously used in paint, or substances that endanger vital species such as bees.

Professor Danil de Namor, University of Surrey Emeritus Professor and leader of the research, said: “Preliminary extraction data are encouraging as far as the use of this receptor for the selective removal of these drugs from water and the possibility of constructing a calix[4]-based sensing devices.

“From here, we can design receptors so that they can bind selectively with pollutants in the water so the pollutants can be effectively removed. This research will allow us to know exactly what is in the water, and from here it will be tested in industrial water supplies, so there will be cleaner water for everyone.

“The research also creates the possibility of using these materials for on-site monitoring of water, without having to transport samples to the laboratory.”

Dr Brendan Howlin, University of Surrey co-investigator, said: “This study allows us to visualise the specific receptor-drug interactions leading to the selective behaviour of the receptor. As well as the health benefits of this research, molecular simulation is a powerful technique that is applicable to a wide range of materials.

“We were very proud that the work was carried out with PhD students and a final year project student, and research activities are already taking place with the Department of Chemical and Processing Engineering (CPI) and the Advanced Technology Institute (ATI).

“We are also very pleased to see that as soon as the paper was published online by the European Journal of Pharmaceutical Sciences, we received invitations to give keynote lectures at two international conferences on pharmaceuticals in Europe later this year.”

That last paragraph is intriguing and it marks the first time I’ve seen that claim in a press release announcing the publication of a piece of research.

Here’s a link to and a citation for the paper,

A calix[4]arene derivative and its selective interaction with drugs (clofibric acid, diclofenac and aspirin) by Angela F Danil de Namor, Maan Al Nuaim, Jose A Villanueva Salas, Sophie Bryant, Brendan Howlin. European Journal of Pharmaceutical Sciences Volume 100, 30 March 2017, Pages 1–8 https://doi.org/10.1016/j.ejps.2016.12.027

This paper is behind a paywall.

Molecular robots (nanobots/nanorobots): a promising start at Oxford University

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‘Baby steps’ is how they are describing the motion and the breakthrough in functional molecular robots at the University of Oxford. From a Dec. 11, 2014 news item on phys.org,

A walking molecule, so small that it cannot be observed directly with a microscope, has been recorded taking its first nanometre-sized steps.

It’s the first time that anyone has shown in real time that such a tiny object – termed a ‘small molecule walker’ – has taken a series of steps. The breakthrough, made by Oxford University chemists, is a significant milestone on the long road towards developing ‘nanorobots’.

‘In the future we can imagine tiny machines that could fetch and carry cargo the size of individual molecules, which can be used as building blocks of more complicated molecular machines; imagine tiny tweezers operating inside cells,’ said Dr Gokce Su Pulcu of Oxford University’s Department of Chemistry. ‘The ultimate goal is to use molecular walkers to form nanotransport networks,’ she says.

A Dec. 10, 2014 University of Oxford science blog post by Pete Wilton, which originated the news item, describes one of the problem with nanorobots,

However, before nanorobots can run they first have to walk. As Su explains, proving this is no easy task.

For years now researchers have shown that moving machines and walkers can be built out of DNA. But, relatively speaking, DNA is much larger than small molecule walkers and DNA machines only work in water.

The big problem is that microscopes can only detect moving objects down to the level of 10–20 nanometres. This means that small molecule walkers, whose strides are 1 nanometre long, can only be detected after taking around 10 or 15 steps. It would therefore be impossible to tell with a microscope whether a walker had ‘jumped’ or ‘floated’ to a new location rather than taken all the intermediate steps.

The post then describes how the researchers solved the problem,

… Su and her colleagues at Oxford’s Bayley Group took a new approach to detecting a walker’s every step in real time. Their solution? To build a walker from an arsenic-containing molecule and detect its motion on a track built inside a nanopore.

Nanopores are already the foundation of pioneering DNA sequencing technology developed by the Bayley Group and spinout company Oxford Nanopore Technologies. Here, tiny protein pores detect molecules passing through them. Each base disrupts an electric current passed through the nanopore by a different amount so that the DNA base ‘letters’ (A, C, G or T) can be read.

In this new research, they used a nanopore containing a track formed of five ‘footholds’ to detect how a walker was moving across it.

‘We can’t ‘see’ the walker moving, but by mapping changes in the ionic current flowing through the pore as the molecule moves from foothold to foothold we are able to chart how it is stepping from one to the other and back again,’ Su explains.

To ensure that the walker doesn’t float away, they designed it to have ‘feet’ that stick to the track by making and breaking chemical bonds. Su says: ‘It’s a bit like stepping on a carpet with glue under your shoes: with each step the walker’s foot sticks and then unsticks so that it can move to the next foothold.’ This approach could make it possible to design a machine that can walk on a variety of surfaces.

There is a video illustrating the molecular walker’s motion, (courtesy University of Oxford),

There is as noted in Wilton’s post, more work to do,

It’s quite an achievement for such a tiny machine but, as Su is the first to admit, there are many more challenges to be overcome before programmable nanorobots are a reality.

‘At the moment we don’t have much control over which direction the walker moves in; it moves pretty randomly,’ Su tells me. ‘The protein track is a bit like a mountain slope; there’s a direction that’s easier to walk in so walkers will tend to go this way. We hope to be able to harness this preference to build tracks that direct a walker where we want it to go.’

The next challenge after that will be for a walker to make itself useful by, for instance, carrying a cargo: there’s already space for it to carry a molecule on its ‘head’ that it could then take to a desired location to accomplish a task.

Su comments: ‘We should be able to engineer a surface where we can control the movement of these walkers and observe them under a microscope through the way they interact with a very thin fluorescent layer. This would make it possible to design chips with different stations with walkers ferrying cargo between these stations; so the beginnings of a nanotransport system.’

These are the first tentative baby steps of a new technology, but they promise that there could be much bigger strides to come.

Here’s a link to and a citation for the research paper,

Continuous observation of the stochastic motion of an individual small-molecule walker by Gökçe Su Pulcu, Ellina Mikhailova, Lai-Sheung Choi, & Hagan Bayley. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.264 Published online 08 December 2014

This paper is behind a paywall.

Phyto-mining and environmental remediation flower in the United Kingdom

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Researchers on a £3 million research programme called “Cleaning Land for Wealth” (CL4W) are confident they’ll be able to use flowers and plants to clean soil of poisonous materials (environmental remediation) and to recover platinum (phyto-mining). From the Nov. 21, 2012 news item on Nanowerk,

A consortium of researchers led by WMG (Warwick Manufacturing Group) at the University of Warwick are to embark on a £3 million research programme called “Cleaning Land for Wealth” (CL4W), that will use a common class of flower to restore poisoned soils while at the same time producing perfectly sized and shaped nano sized platinum and arsenic nanoparticles for use in catalytic convertors, cancer treatments and a range of other applications.

The Nov. 20, 2012 University of Warwick news release, which originated the news item, describes both how CL4W came together and how it produced an unintended project benefit,

A “Sandpit” exercise organised by the Engineering and Physical Sciences Research Council (EPSRC) allowed researchers from WMG (Warwick Manufacturing group) at the University of Warwick, Newcastle University, The University of Birmingham, Cranfield University and the University of Edinburgh to come together and share technologies and skills to come up with an innovative multidisciplinary research project that could help solve major technological and environmental challenges.

The researchers pooled their knowledge of how to use plants and bacteria to soak up particular elements and chemicals and how to subsequently harvest, process and collect that material. They have devised an approach to demonstrate the feasibility in which they are confident that they can use common classes of flower and plants (such as Alyssum), to remove poisonous chemicals such as arsenic and platinum from polluted land and water courses potentially allowing that land to be reclaimed and reused.

That in itself would be a significant achievement, but as the sandpit progressed the researchers found that jointly they had the knowledge to achieve much more than just cleaning up the land.

As lead researcher on the project Professor Kerry Kirwan from WMG at the University of Warwick explained:

“The processes we are developing will not only remove poisons such as arsenic and platinum from contaminated land and water courses, we are also confident that we can develop suitable biology and biorefining processes (or biofactories as we are calling them) that can tailor the shapes and sizes of the metallic nanoparticles they will make. This would give manufacturers of catalytic convertors, developers of cancer treatments and other applicable technologies exactly the right shape, size and functionality they need without subsequent refinement. We are also expecting to recover other high value materials such as fine chemicals, pharmaceuticals, anti-oxidants etc. from the crops during the same biorefining process.”

I last mentioned phyto-mining in my Sept. 26, 2012 post with regard to an international project being led by researchers at the University of York (UK).  The biorefining processes (biofactories) mentioned by Kirwan takes the idea of recovering platinum, etc. one step beyond phyto-mining recovery.

Here’s a picture of the flower (Alyssum) mentioned in the news release,

Alyssum montanum photographed by myself in 1988, Unterfranken, Germany [http://en.wikipedia.org/wiki/Alyssum]

From the Wikipedia essay (Note: I have removed links],

Alyssum is a genus of about 100–170 species of flowering plants in the family Brassicaceae, native to Europe, Asia, and northern Africa, with the highest species diversity in the Mediterranean region. The genus comprises annual and perennial herbaceous plants or (rarely) small shrubs, growing to 10–100 cm tall, with oblong-oval leaves and yellow or white flowers (pink to purple in a few species).

Rosie Redfield talks #arseniclife at Vancouver’s Café Scientifique tonight (April 24, 2012)

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Rose Redfield seems to be everywhere in Vancouver these days. Last week (April 19, 2012) she spoke at the first ScienceOnline Vancouver Event and tonight she’s at Café Scientifique at the Railway Club, 579 Dunsmuir St. (second floor) at 7:30 pm.

Here’s the event description straight from the news release,

Our speaker for the evening will be Dr. Rosie Redfield, the biologist from UBC who was recently named one of the “10 People Who Mattered” in 2011 by Nature magazine. (http://www.nature.com/news/365-days-nature-s-10-1.9678 ).

The title and abstract for her café is:

#arseniclife and Open Science
The #arseniclife story started with a bang in late 2010, when NASA proudly announced the discovery that some bacteria could synthesize their DNA with arsenic in the backbone in place of phosphorus. But within a few days it all fell apart, as scientists used blogs and Twitter to conduct impromptu ‘post-publication peer review’. (‘#arseniclife’ is the Twitter hashtag used to identify relevant tweets.) Working with collaborators at Princeton, my lab has now shown that the key results cannot be replicated. This debacle has implications for many aspects of science, from how personal biases and funding sources affect scientific judgment to the increasing roles of social media in both the practice and public communication of science.

I hope she’s addressed that problem with overmodulation that I described in my comments about last week’s ScienceOnline Vancouver event (my April 20, 2012 posting) because she’s very interesting.

For anyone not familiar with the #arseniclife story, here’s my Dec. 8, 2012 apology  posting about it (with links to other more informed writing) and my blooper Dec. 6, 2010 posting.

Comments on ScienceOnline Vancouver’s first event

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Bravo to the organizers, Catherine Anderson, Sarah Chow, and Peter Newberry of Vancouver’s (Canada) first ScienceOnline event last night (Thursday, April 19, 2012 first mentioned my April 4, 2012 posting). They attracted, by my count,  a crowd of about 75-80 people. A free event held at Science World, there were three speakers Rosie Redfield, Lisa Johnson, and Anthony Floyd. Here’s a bit more about them from the event description page,

  • Rosie Redfield – Named Nature’s most influential person of 2011, this associate professor of microbiology at UBC [University of British Columbia] hit science fame through her blog RRResearch disputing NASA’s claim life exists in arsenic.
  • Lisa Johnson – Multiplatform journalist with a keen interest in environment and science stories. She enjoys digging, storytelling, and finding context in breaking news.
  • Anthony Floyd – aerospace research engineer with a PhD in Civil Engineering from UBC. Although strictly a digital immigrant, Anthony grew up with technology as technology grew up. He is quite active in social media. Anthony’s a proud dad to two boys, year-round bike commuter, opinionated political observer, and Maritimer-in-exile.

The event was titled, Where do you get your science? It was the third event I attended yesterday so maybe I was a little less tolerant than I can be. I was expecting a lively discussion about finding science what I got was Redfield and Johnson talking about the arsenic life story and their roles in that story locally and, in Redfield’s case, internationally. The only one who really talked about finding science online was Floyd.

I’m not sure if the organizers were hoping that the ‘arsenic life’ stories would somehow tie into the topic or if the two speakers just went off on their own tangents.

Redfield gave an ‘ignite’ talk, which is five minutes long with 20 slides in a timed slideshow where the speaker has to keep time with the slides. I’m sorry to say she overmodulated (used the storytime voice usually aimed at an audience of five-year olds)  for much of the talk. Johnson made the point several times that it wasn’t her fault that the story was wrong. She did admit at one point that she could have dug more deeply and, in fact, someone suggested that she talk to Rosie Redfield for advice about this story at very early stage, something she failed to do. Most valuable to me was the reminder of the constraints that journalists are under.

Note: I, too,  got caught up with my Dec. 6, 2010 posting and I subsequently apologized, Dec. 8, 2010 posting.

Floyd, as I noted earlier, did address the question, Where do you get your science?, although he did ask his audience to make a bit of a leap when he used a story about searching for information about bicycle helmets and bylaws to illustrate one of his points.

I wasn’t able to stay for the more informal discussion after the speakers finished but the organizers  did manage a good icebreaker exercise at the beginning. The audience seemed * to be mostly in their 20s and 30s.

It was a very technology-heavy event in that there was livestreaming, multiple computers and screens, references to tweeting and Storify, etc.

Aside: All three of the events I attended yesterday had technology issues of one kind or another. I’m not especially happy when almost all of the attention is on the technology while the live audience is left waiting or is interrupted during question period to accommodate a tweet or has to endure feedback.

I did mention Storify, the ScienceOnline Vancouver Storify ‘story’ is here and you can check #sovan on Twitter for other responses to last night’s event.

All in all, it was a very promising start, despite my nitpicks.

*Removed a redundant work ‘mostly’ on January 14, 2020.